The bandwidth shortage increasingly experienced by mobile carriers has motivated the exploration of the underutilized millimeter wave (mmW) frequency spectrum between 6 G and 300 G Hz for the next generation broadband cellular communication networks. The available spectrum of mmW band is two hundred times greater than the conventional cellular system. The mmW wireless network uses directional communications with narrow beams and can support multi-gigabit data rate. The underutilized bandwidth of the mmW spectrum has wavelengths ranging from 1 mm to 100 mm. The very small wavelengths of the mmW spectrum enable a large number of miniaturized antennas to be placed in a small area. Such miniaturized antenna system can produce high beamforming gains through electrically steerable arrays generating directional transmissions.
With recent advances in mmW semiconductor circuitry, mmW wireless system has become a promising solution for the real implementation. However, the heavy reliance on directional transmissions presents particular challenges for the mobile stations in the mmW network. Unlike the traditional cellular system, the mmW cell is covered by one or more than one directional beams. Therefore, the synchronization and broadcast signals for a cell are also directional and only cover a small area. The mobile stations need to scan over a range of angles before a cell can be detected. The traditional RRM measurement procedure is not applicable for mmW system.
Improvements and enhancements are required to enhance radio resource management (RRM) mechanism in the millimeter wave (mmW) system.